Negative electrode active material of lithium secondary battery, secondary battery using the same, method for manufacturing the same

Abstract

A negative electrode active material of lithium secondary battery includes: at least one of a petroleum-derived green coke and a coal-derived green coke, and at least one of a petroleum-derived calcined coke and a coal-derived calcined coke within a mass ratio range of 90:10 to 10:90, and a phosphorous compound within a range of 0.1 to 6.0 parts by mass in amount equivalent to phosphor relative to 100 parts by mass of the at least one of the green cokes and the at least one of the calcined cokes.

What is claimed is: 
     
       1. A negative electrode active material of lithium secondary battery, consisting of:
 a coal-derived green coke, and 
 a coal-derived calcined coke, wherein a mass ratio of said green coke to said calcined coke is in a range of from 90:10 to 10:90; and 
 a phosphorous compound, said phosphorous compound being present in an amount in a range of from 0.1:100 to 6.0:100 parts by mass relative to the mass of said green coke and said calcined coke. 
 
     
     
       2. The negative electrode active material as set forth in  claim 1 ,
 wherein the mass ratio of said green coke to said calcined coke in a range of from 70:30 to 30:70. 
 
     
     
       3. The negative electrode active material as set forth in  claim 1 ,
 wherein the amount of said phosphorous compound is in a range of from 0.5:100 to 5.0:100 parts by mass relative to the mass of said green coke and said calcined coke. 
 
     
     
       4. The negative electrode active material as set forth in  claim 1 , wherein
 said green coke is a powdery green coke, and said calcined coke is a powdery calcined coke. 
 
     
     
       5. The negative electrode active material as set forth in  claim 4 ,
 wherein said powdery green coke has a BET specific surface area of 5 m 2 /g or less and said powdery calcined coke has a BET specific surface area of 5 m 2 /g or less. 
 
     
     
       6. The negative electrode active material as set forth in  claim 4 ,
 wherein said powdery green coke has an average particle diameter within a range of 5 to 15 μm and said powdery calcined coke has an average particle diameter within a range of 5 to 15 μm. 
 
     
     
       7. The negative electrode active material as set forth in  claim 1 , exhibiting an intensity ratio of a diffraction peak in the vicinity of 1360 cm −1  to a diffraction peak in the vicinity of 1580 cm −1  within a range of 1.1 to 1.4, the diffraction peaks being obtained by means of Raman spectroscopy. 
     
     
       8. A secondary battery for vehicle installation comprising a negative electrode active material of lithium secondary battery as set forth in  claim 1 . 
     
     
       9. The secondary battery as set forth in  claim 8 ,
 wherein said negative electrode active material is used for at least one of an electric vehicle and a storage battery for electric power storage. 
 
     
     
       10. A method for manufacturing a negative electrode active material of lithium secondary battery, consisting of the steps of:
 mixing a coal-derived green coke and a coal-derived calcined coke to form a coke mixture, wherein a mass ratio of said green coke to said calcined coke in the coke mixture is in a range of from 90:10 to 10:90, 
 adding a phosphorous compound to the coke mixture, said phosphorous compound being present in the coke mixture in an amount in a range of from 0.1:100 to 6.0:100 parts by mass relative to the mass of said green coke and said calcined coke; and 
 firing the coke mixture with said phosphorous compound added therein. 
 
     
     
       11. The manufacturing method as set forth in  claim 10 ,
 wherein the coke mixture with said phosphorous compound added therein is fired at a temperature within a temperature range of from 800 to 1400° C. 
 
     
     
       12. The manufacturing method as set forth in  claim 10 ,
 wherein the mass ratio of said green coke to said calcined coke is in a range of from 70:30 to 30:70. 
 
     
     
       13. The manufacturing method as set forth in  claim 10 , wherein the amount of said phosphorous compound that is present in the coke mixture is in a range of from 0.5:100 to 5.0:100 parts by mass relative to the mass of said green coke and said calcined coke. 
     
     
       14. A negative electrode active material of lithium secondary battery, consisting of:
 a coal-derived green coke; 
 a coal-derived calcined coke, wherein a mass ratio of said green coke to said calcined coke is in a range of 90:10 to 10:90; 
 a phosphorous compound, said phosphorus compound being present in an amount in a range of 0.1:100 to 6.0:100 relative to the mass of said green coke and said calcined coke; and 
 a hydrogen content, said hydrogen content being present in an amount in a range of 3000 ppm or less. 
 
     
     
       15. A method for manufacturing a negative electrode active material of lithium secondary battery, consisting of the steps of:
 pulverizing a coal-derived green coke and a coal-derived calcined coke to make a powdery green coke and a powdery calcined coke, 
 mixing said powdery green coke and said powdery calcined coke to form a coke mixture, wherein a mass ratio of said powdery green come to said powdery calcined coke in the coke mixture is in a range from 90:10 to 10:90, 
 adding a phosphorous compound to the coke mixture, said phosphorous compound being present in the coke mixture in an amount in a range of from 0.1:100 to 6.0:100 parts by mass relative to the mass of said green coke and said calcined coke; and 
 firing the coke mixture with said phosphorous compound added therein.